1. Field of Invention
The present invention pertains to the field of optical bubble switches. More particularly, this invention relates to heating of trenches in optical bubble switches.
2. Art Background
A typical optical bubble switch includes a layer of waveguides for conducting light and a structure for altering the routing of light through the waveguides. A structure that contains the waveguides is commonly referred to as a planar light wave circuit (PLC) and a structure that alters the routing of light through the waveguides of a PLC is commonly referred to as a matrix controller chip (MCC).
The PLC of a typical optical bubble switch includes trenches formed through the waveguide layer. Typically, a fluid is disposed between the PLC and MCC which fills in the trenches and facilitates the flow of light through the waveguides. The MCC under control of switching circuitry usually heats the fluid in selected areas causing the formation of bubbles in selected trenches. A bubble formed in a trench usually changes the refractive index of the trench, thereby altering the flow of light in the waveguide layer.
In prior optical bubble switches, the electrical power needed to form bubbles is usually carried via conductive lines in the MCC. The electrical current flow through these lines usually causes undesirable amounts of power dissipation and limits the number of switching elements that may be implemented in a bubble switch array.
In addition, prior optical bubble switches may suffer from the incomplete formation of bubbles in its trenches. Unfortunately, a less than fully formed bubble can still leave traces of fluid on the edges of a trench and cause undesirable switching characteristics.